C multisocket program not working - c

Question

I am trying to create a simple client/server socket-based program. It's just a basic "Guess the number" game, where the server comes up with a number and then the client(s) try to guess the number. The problem is that I am having problems with the programs working as intended.
The problem is such: When I launch up the server program and it generates the random number, I try loading up the client programs, but after one input, they stop working. It stops after outputting this:
Guess: 42
Buffer to be processed : <42
>
integerGuess : <42>
String Guess : <42\n>
Buffer to send : <42\n>
Here's the server.c file code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <time.h> /* time for randomizer*/
void error(const char *msg)
{
perror(msg);
exit(1);
}
int main(int argc, char *argv[])
{
int sockfd, newsockfd, portno, n;
socklen_t clilen;
char buffer[256];
struct sockaddr_in serv_addr, cli_addr;
int GuessedInteger, integerRandom, serverFlagCorrect;
char charGuess[4], answerServer[1];
char* delimiter = "\\n";
/** initialization of variables **/
serverFlagCorrect = 0;
/** generate random integer from 1 to 100 **/
srand (time(NULL));
integerRandom = (rand() % 100) + 1;
printf("This is the random integer : %d \n", integerRandom);
if (argc < 2) {
fprintf(stderr,"ERROR, no port provided\n");
exit(1);
}
// Creates the socket socket() --> endpoints of sockets
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd < 0)
error("ERROR opening socket");
// Creates the socket socket() --> endpoints of sockets
// assign unique new address
bzero((char *) &serv_addr, sizeof(serv_addr));
portno = atoi(argv[1]);
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = INADDR_ANY;
serv_addr.sin_port = htons(portno);
if (bind(sockfd, (struct sockaddr *) &serv_addr,
sizeof(serv_addr)) < 0)
error("ERROR on binding");
// assign unique new address
// wait for a connection
listen(sockfd,5);
// wait for a connection
// accepts the connection
clilen = sizeof(cli_addr);
while (1) {
newsockfd = accept(sockfd,
(struct sockaddr *) &cli_addr, &clilen);
if (newsockfd < 0)
error("ERROR on accept");
n = fork();
if (n < 0)
error("ERROR on fork");
if (n == 0) {
close(sockfd);
dostuff(newsockfd);
exit(0);
}
else close(newsockfd);
} /* end of while */
close(sockfd);
return 0; /* we never get here */
}
void dostuff (int sock) {
int GuessedInteger, integerRandom, serverFlagCorrect;
char charGuess[4], answerServer[1];
char* delimiter = "\\n";
int sockfd, newsockfd, portno, n;
socklen_t clilen;
char buffer[256];
struct sockaddr_in serv_addr, cli_addr;
while (serverFlagCorrect != 1)
{
// reads the data being received
bzero(buffer,256);
n = read(newsockfd,buffer,255);
if (n < 0) error("ERROR reading from socket");
// reads the data being received
printf("Buffer from client: <%s>\n", buffer);
memcpy(charGuess, buffer, sizeof(charGuess));
printf("Message from client in charGuess: <%s>\n", charGuess);
/* Put if statement here for error out if no \n at the end */
int len = strlen(charGuess);
const char *last_two = &charGuess[len-2];
printf("Last two characters of charGuess: <%s>\n", last_two);
if (strncmp ( last_two, delimiter, 2) )
error (" ERROR Wrong protocol received");
/** turn string to int for comparison **/
GuessedInteger = atoi(charGuess);
printf("Guessed Integer : %d \n", GuessedInteger);
/** Server response for comparison**/
if (GuessedInteger > integerRandom)
memcpy(&answerServer, "Lower", sizeof(answerServer));
else if (GuessedInteger < integerRandom)
memcpy(&answerServer, "Higher", sizeof(answerServer));
else if (GuessedInteger == integerRandom)
{
serverFlagCorrect = 1;
memcpy(&answerServer, "Correct", sizeof(answerServer));
}
printf("Value of answerServer: %c\n", *answerServer);
/** Server response for comparison**/
// sends the answer
n = write(newsockfd, answerServer, 1);
if (newsockfd < 0)
error("ERROR on accept");
// sends the answer
// closes what was sent
}
close(newsockfd);
}
Here's the client.c code:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
void error(const char *msg)
{
perror(msg);
exit(0);
}
int main(int argc, char *argv[])
{
int sockfd, portno, n;
struct sockaddr_in serv_addr;
struct hostent *server;
char buffer[1024];
int integerGuess, clientFlagCorrect;
int numberOfTries;
char charGuess[1024], answerServer[1];
char* delimiter = "\\n";
if (argc < 3) {
fprintf(stderr,"usage %s hostname port\n", argv[0]);
exit(0);
}
portno = atoi(argv[2]);
// Creates the socket socket() --> endpoints of sockets
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd < 0)
error("ERROR opening socket");
// Creates the socket socket() --> endpoints of sockets
server = gethostbyname(argv[1]);
if (server == NULL) {
fprintf(stderr,"ERROR, no such host\n");
exit(0);
}
// connects to the service in connect()
bzero((char *) &serv_addr, sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
bcopy((char *)server->h_addr,
(char *)&serv_addr.sin_addr.s_addr,
server->h_length);
serv_addr.sin_port = htons(portno);
if (connect(sockfd,(struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0)
error("ERROR connecting");
// connects to the service
/** variables **/
clientFlagCorrect = 0;
numberOfTries = 0;
while (clientFlagCorrect != 1)
{
numberOfTries = numberOfTries + 1;
/** initializing vars **/
integerGuess = 0;
memset(charGuess, 0, sizeof(charGuess));
// ask for the number
printf("Guess: ");
bzero(buffer,sizeof(buffer));
fgets(buffer,sizeof(buffer)-1,stdin);
printf("Buffer to process is : <%s>\n", buffer);
// ask to see if the number is guessed
/** string and delimeter **/
integerGuess = atoi(buffer);
printf("int Guess : <%d> \n", integerGuess);
sprintf( charGuess, "%d", integerGuess);
strcat( charGuess, delimiter);
printf("String Guess : <%s> \n", charGuess);
memset(buffer,0,sizeof(buffer));
memcpy(buffer, charGuess, sizeof(charGuess));
printf("Buffer to be sent is: : <%s>\n",buffer);
/** process the integer to string and add a delimiter **/
// send the string that was processed
n = write(sockfd,buffer,strlen(buffer));
if (n < 0)
error("ERROR writing to socket");
// send the string that was processed
// reads the data being received
bzero(buffer,256);
n = read(sockfd,buffer,255);
if (n < 0)
error("ERROR reading from socket");
// reads the data being received
printf("Buffer received : <%s>\n",buffer);
memcpy(&answerServer, buffer, sizeof(answerServer));
printf ("Value of answerServer : <%c> \n", *answerServer);
/** Client response **/
if (strncmp ( & answerServer[0],"Lower",sizeof(answerServer)) == 0)
printf("The number is lower \n");
else if (strncmp ( & answerServer[0],"Higher",sizeof(answerServer)) == 0)
printf("The number is higher \n");
else if (strncmp ( & answerServer[0],"Correct",sizeof(answerServer)) == 0)
{
printf("Your guess is correct! \n");
clientFlagCorrect = 1;
}
else
error("ERROR Wrong message received");
}
printf ("It took you this many tries: %d \n", numberOfTries);
printf("%s\n",buffer);
close(sockfd);
return 0;
}
Any help would be greatly appreciated.
EDIT: After some extra work and "Debugging" (consisting mostly of me adding a load of printf's at various points) I am 90% convinced the problem is on the server side. I added printf's before and after this line:
printf("This is the random integer : %d \n", integerRandom);
And found that while the printf immediately before the line prints out fine, placing one right below it only prints it if prints out the "No port detected" error. Any further printf's don't trigger at all, which means that the program doesn't even reach the main loop that does the program.
As for the client file, it reached the line:
printf("Buffer to be sent is: : <%s>\n",buffer);
And stops (Once again via printf's). Why, I honestly have no clue. Which means there's a problem somewhere around those points, but where, I honestly have no clue.